https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93401
--- Comment #2 from Martin Liška <marxin at gcc dot gnu.org> --- Confirmed. I would suggest to either an option that will tell which prefix should be stripped from the .gcda files, or how many path components to skip. Will it work for FF and HHVM? I'm not sure FF uses a prefix map?